net/bridge/netfilter/ebt_log.c

   1 /*
   2  *  ebt_log
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer <bdschuym@pandora.be>
   6  *
   7  *  April, 2002
   8  *
   9  */
  10
  11 #include <linux/netfilter_bridge/ebtables.h>
  12 #include <linux/netfilter_bridge/ebt_log.h>
  13 #include <linux/module.h>
  14 #include <linux/ip.h>
  15 #include <linux/if_arp.h>
  16 #include <linux/spinlock.h>
  17
  18 static DEFINE_SPINLOCK(ebt_log_lock);
  19
  20 static int ebt_log_check(const char *tablename, unsigned int hookmask,
  21    const struct ebt_entry *e, void *data, unsigned int datalen)
  22 {
  23         struct ebt_log_info *info = (struct ebt_log_info *)data;
  24
  25         if (datalen != EBT_ALIGN(sizeof(struct ebt_log_info)))
  26                 return -EINVAL;
  27         if (info->bitmask & ~EBT_LOG_MASK)
  28                 return -EINVAL;
  29         if (info->loglevel >= 8)
  30                 return -EINVAL;
  31         info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
  32         return 0;
  33 }
  34
  35 struct tcpudphdr
  36 {
  37         uint16_t src;
  38         uint16_t dst;
  39 };
  40
  41 struct arppayload
  42 {
  43         unsigned char mac_src[ETH_ALEN];
  44         unsigned char ip_src[4];
  45         unsigned char mac_dst[ETH_ALEN];
  46         unsigned char ip_dst[4];
  47 };
  48
  49 static void print_MAC(unsigned char *p)
  50 {
  51         int i;
  52
  53         for (i = 0; i < ETH_ALEN; i++, p++)
  54                 printk("%02x%c", *p, i == ETH_ALEN - 1 ? ' ':':');
  55 }
  56
  57 #define myNIPQUAD(a) a[0], a[1], a[2], a[3]
  58 static void ebt_log(const struct sk_buff *skb, unsigned int hooknr,
  59    const struct net_device *in, const struct net_device *out,
  60    const void *data, unsigned int datalen)
  61 {
  62         struct ebt_log_info *info = (struct ebt_log_info *)data;
  63         char level_string[4] = "< >";
  64         union {struct iphdr iph; struct tcpudphdr ports;
  65                struct arphdr arph; struct arppayload arpp;} u;
  66
  67         level_string[1] = '0' + info->loglevel;
  68         spin_lock_bh(&ebt_log_lock);
  69         printk(level_string);
  70         printk("%s IN=%s OUT=%s ", info->prefix, in ? in->name : "",
  71            out ? out->name : "");
  72
  73         printk("MAC source = ");
  74         print_MAC(eth_hdr(skb)->h_source);
  75         printk("MAC dest = ");
  76         print_MAC(eth_hdr(skb)->h_dest);
  77
  78         printk("proto = 0x%04x", ntohs(eth_hdr(skb)->h_proto));
  79
  80         if ((info->bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
  81            htons(ETH_P_IP)){
  82                 struct iphdr _iph, *ih;
  83
  84                 ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
  85                 if (ih == NULL) {
  86                         printk(" INCOMPLETE IP header");
  87                         goto out;
  88                 }
  89                 printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u,",
  90                    NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));
  91                 printk(" IP tos=0x%02X, IP proto=%d", u.iph.tos,
  92                        ih->protocol);
  93                 if (ih->protocol == IPPROTO_TCP ||
  94                     ih->protocol == IPPROTO_UDP) {
  95                         struct tcpudphdr _ports, *pptr;
  96
  97                         pptr = skb_header_pointer(skb, ih->ihl*4,
  98                                                   sizeof(_ports), &_ports);
  99                         if (pptr == NULL) {
 100                                 printk(" INCOMPLETE TCP/UDP header");
 101                                 goto out;
 102                         }
 103                         printk(" SPT=%u DPT=%u", ntohs(pptr->src),
 104                            ntohs(pptr->dst));
 105                 }
 106                 goto out;
 107         }
 108
 109         if ((info->bitmask & EBT_LOG_ARP) &&
 110             ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
 111              (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
 112                 struct arphdr _arph, *ah;
 113
 114                 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
 115                 if (ah == NULL) {
 116                         printk(" INCOMPLETE ARP header");
 117                         goto out;
 118                 }
 119                 printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
 120                        ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
 121                        ntohs(ah->ar_op));
 122
 123                 /* If it's for Ethernet and the lengths are OK,
 124                  * then log the ARP payload */
 125                 if (ah->ar_hrd == htons(1) &&
 126                     ah->ar_hln == ETH_ALEN &&
 127                     ah->ar_pln == sizeof(uint32_t)) {
 128                         struct arppayload _arpp, *ap;
 129
 130                         ap = skb_header_pointer(skb, sizeof(u.arph),
 131                                                 sizeof(_arpp), &_arpp);
 132                         if (ap == NULL) {
 133                                 printk(" INCOMPLETE ARP payload");
 134                                 goto out;
 135                         }
 136                         printk(" ARP MAC SRC=");
 137                         print_MAC(ap->mac_src);
 138                         printk(" ARP IP SRC=%u.%u.%u.%u",
 139                                myNIPQUAD(ap->ip_src));
 140                         printk(" ARP MAC DST=");
 141                         print_MAC(ap->mac_dst);
 142                         printk(" ARP IP DST=%u.%u.%u.%u",
 143                                myNIPQUAD(ap->ip_dst));
 144                 }
 145         }
 146 out:
 147         printk("\n");
 148         spin_unlock_bh(&ebt_log_lock);
 149 }
 150
 151 static struct ebt_watcher log =
 152 {
 153         .name           = EBT_LOG_WATCHER,
 154         .watcher        = ebt_log,
 155         .check          = ebt_log_check,
 156         .me             = THIS_MODULE,
 157 };
 158
 159 static int __init init(void)
 160 {
 161         return ebt_register_watcher(&log);
 162 }
 163
 164 static void __exit fini(void)
 165 {
 166         ebt_unregister_watcher(&log);
 167 }
 168
 169 module_init(init);
 170 module_exit(fini);
 171 MODULE_LICENSE("GPL");